Synthesis, microstructure and mechanical properties of ceria stabilized tetragonal zirconia prepared by spray drying technique

摘要

Ceria stabilized zirconia powders with ceria concentration varying from 6 to 16 mol percent were synthesized using spray drying technique. Powders were characterized for their particle size distribution and specific surface area. The dense sintered ceramics fabricated using these powders were characterized for their microstructure, crystallite size and phase composition. The flexural strength, fracture toughness and micro-hardness of sintered ceramics were measured. High fracture toughness and flexural strength were obtained for sintered bodies with 12 mol percent of CeO_2. Flexural strength and fracture toughness were dependent on CeO_2 concentration, crystallite size and phase composition of sintered bodies. Correlation of data has indicate that the transformable tetragonal phase is the key factor in controlling the fracture toughness and strength of ceramics. It has been demonstrated that the synthesis methods is effective to prepare nanocrystalline tetragonal ceria stabilized zirconia powders with improved mechanical properties. Ce-ZrO_2 with 20 wt percent alumina was also prepared with flexural strength, 1200 MPa and fracture toughness, 9.2 MPa√m.